Coating composition with improved adhesion to friable surfaces

ABSTRACT

An aqueous coating composition having improved adhesion to friable surfaces including an emulsion polymer of certain compositions and certain acid numbers having a glass transition temperature of −20 C to 100 C and an average particle diameter less than 120 nanometers; and 0.25-10%, by weight based on emulsion polymer weight, water-soluble alkoxylated amine is provided. In addition a method for for improving adhesion to friable surfaces by using the aqueous coating compositions of the invention is provided.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of Provisional Application No.60/133,098, filed May 7, 1999.

This is a non-provisional division application of prior U.S. provisionalapplication Ser. No. 09/552,877 filed Apr. 20, 2000 now U.S. Pat. No.6,660,801.

This invention relates to an aqueous coating composition having improvedadhesion to friable surfaces such as chalky weathered paint surfaces andmasonry surfaces. More particularly, this invention relates to anaqueous coating composition including an emulsion polymer of selectedcomposition having a glass transition temperature (Tg) of −20 C to 100 Cand an average particle diameter less than 120 nanometers, and 0.25-10wt. % of a water-soluble alkoxylated amine. And the invention relates toa method for improving the adhesion of a dried aqueous coatingcomposition to a friable surface by forming an aqueous coatingcomposition including an emulsion polymer of selected composition havinga glass transition temperature (Tg) of −20 C to 100 C and an averageparticle diameter less than 120 nanometers, and 0.25-10% of awater-soluble alkoxylated amine; applying the aqueous coatingcomposition to a friable surface; and drying, or allowing to dry, theaqueous coating composition.

The present invention serves to provide a dried coating which hasimproved adhesion to a friable surface. Coatings are frequentlydesirably applied to surfaces which are both porous and weak, i.e.,subject to attrition on abrasion such as, for example, chalky surfacesof coatings which have weathered to an extent that poorly consolidatedpigment forms a surface layer on the coating and masonry surfaces,weathered or not, which have a poorly consolidated surface. A substrateto which a coating is applied may have an entirely friable surface oronly portions of the surface may be friable. Such substrates present aproblem to the applicator in that, without being bound by thismechanism, the aqueous coating composition may not penetrate the weakboundary layer of the friable surface or friable surface areassufficiently to provide a dry coating with the requisite degree ofadhesion to the substrate below the weak surface.

U.S. Pat. No. 4,771,100 discloses the use of ethoxylated fatty amines inthe preparation of latexes containing about 0.1 to 10 weight percent ofcopolymerized carboxylic acid monomer which have particle sizes between889 and 1091 Angstroms for use as coatings. Improved adhesion to friablesurfaces is desired.

Adhesion to a substrate to which it has been applied is a generallydesirable characteristic of a coating. However, some surfaces arenotoriously difficult to adhere to and coatings which adhere well tosound surfaces will fail to adhere to such surfaces. One such difficultsurface is a friable surface, that is, one on which a weak, poorlybound, inadequately consolidated surface layer such as a badly chalkingweathered paint surface or a brittle, crumbling masonry surface, is tobe coated. The problem faced by the inventors is the provision of asuitable aqueous coating composition and a method for improving theadhesion of a coating so that that adhesion to friable surfaces can beeffected. We have now found that that certain polymer compositions usedin conjunction with water-soluble alkoxylated amines provide improvedadhesion to friable surfaces relative to alternative compositions.

In a first aspect of the present invention there is provided an aqueouscoating composition having improved adhesion to friable surfacesincluding an emulsion polymer having a glass transition temperature of−20 C to 100 C and an average particle diameter less than 120nanometers, the emulsion polymer having at least one copolymerizedethylenically unsaturated nonionic monomer, each of the nonionicmonomer(s) having a water solubility less than 8%, and at least onecopolymerized acid monomer, such that the acid number of the emulsionpolymer is 30 to 100; and 0.25-10%, by weight based on the emulsionpolymer weight, water-soluble alkoxylated amine.

In a second aspect of the present invention there is provided an aqueouscoating composition having improved adhesion to friable surfacesincluding an emulsion polymer having a glass transition temperature of−20 C to 100 C and an average particle diameter less than 120nanometers, the emulsion polymer having 8-99.5%, by weight based on theweight of the emulsion polymer, of at least one copolymerizedethylenically unsaturated first nonionic monomer, each of the firstnonionic monomer(s) having a water solubility of 8% or more, 0-91.5%, byweight based on the weight of the emulsion polymer, of at least onecopolymerized ethylenically unsaturated second nonionic monomer, each ofthe second nonionic monomer(s) having a water solubility of less than8%, and at least one copolymerized acid monomer, such that the acidnumber of the emulsion polymer is 4 to 100; and 0.25-10%, by weightbased on the emulsion polymer weight, water-soluble alkoxylated amine.

In a third aspect of the present invention there is provided a methodfor improving the adhesion of a dried aqueous coating composition to afriable surface including forming an aqueous coating compositionincluding an emulsion polymer having a glass transition temperature of−20 C to 100 C and an average particle diameter less than 120nanometers, the emulsion polymer having at least one copolymerizedethylenically unsaturated nonionic monomer, each of said nonionicmonomer(s) having a water solubility less than 8%, and at least onecopolymerized acid monomer, such that the acid number of the emulsionpolymer is 30 to 100, and 0.25-10%, by weight based on polymer weight,water-soluble alkoxylated amine; applying the aqueous coatingcomposition to a surface; and drying, or allowing to dry, the aqueouscoating composition.

In a fourth aspect of the present invention there is provided a methodfor improving the adhesion of a dried aqueous coating composition to afriable surface by forming an aqueous coating composition including anemulsion polymer having a glass transition temperature of −20 C to 100 Cand an average particle diameter less than 120 nanometers, the emulsionpolymer having 8-99.5%, by weight based on the weight of the emulsionpolymer, of at least one copolymerized ethylenically unsaturated firstnonionic monomer, each of the first nonionic monomer(s) having a watersolubility of 8% or more, 0-91.5%, by weight based on the weight of theemulsion polymer, of at least one copolymerized ethylenicallyunsaturated second nonionic monomer, each of the second nonionicmonomer(s) having a water solubility of less than 8%, and at least onecopolymerized acid monomer, such that the acid number of the emulsionpolymer is 4 to 100, and 0.25-10%, by weight based on polymer weight,water-soluble alkoxylated amine; applying the aqueous coatingcomposition to a surface; and drying, or allowing to dry, the aqueouscoating composition

The aqueous coating composition contains a waterborne emulsion polymer.The emulsion polymer contains at least one copolymerized nonionicethylenically-unsaturated monomer, such as, for example, a (meth)acrylicester monomer including methyl acrylate, ethyl acrylate, butyl acrylate,2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, butylmethacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate,aminoalkyl (meth)acrylate; styrene or substituted styrenes; butadiene;vinyl acetate or other vinyl esters; vinyl monomers such as vinylchloride, vinylidene chloride, N-vinyl pyrollidone; (meth)acrylonitrileand (meth)acrylamide. The use of the term “(meth)” followed by anotherterm such as acrylate or acrylamide, as used throughout the disclosure,refers to both acrylates and acrylamides and methacrylates andmethacrylamides, respectively.

The water solubility of the nonionic monomers incorporated into theemulsion polymers herein are defined as those determined using theQuantitative Structural Activity Relationship (QSAR) program. Theprogram uses the molecular structure to estimate physical-chemicalproperties including, molecular weight, vapor pressure, solubility,bioconcentration factor, hydrolysis half-life, Henry's coefficient,partitioning data, and other parameters (based on Lyman, W., Reehl, W.,and Rosenblatt, D. Handbook of Chemical Property Estimation Methods.Chapter 2 “Solubility in Water”. McGraw Hill Book Co., New York, 1982).The QSAR database used to calculate the water solubility assessment ismaintained by the Institute for Process Analysis, Montana StateUniversity (Bozeman, Mont., USA) and accessed through Tymnet DataSystems and Numerica Online Systems (Numericom. 1994. The OnlineInterface for Numerica Users. Technical Data Base Services, Inc. (TDS,135 West 50th Street, New York, N.Y. 10020). Some water solubilities arepresented in Table 1.

TABLE 1 Water solubilities of monomers Water Solubility by QSAR MethodMonomer (grams per 100 grams of water) BA 0.465 EA 2.88 EHA 0.0172 MMA4.17 Sty 0.0672 VA 9.65 AAEM 8.00

The emulsion polymer has a certain acid number range resulting from atleast one copolymerized monoethylenically-unsaturated acid monomer suchas, for example, acrylic acid, methacrylic acid, crotonic acid, itaconicacid, sulfoethyl methacrylate, phosphoroethyl methacrylate, fumaricacid, maleic acid, monomethyl itaconate, monomethyl fumarate, monobutylfumarate, and maleic anhydride. The acid number of the emulsion polymerof the first and third aspects of the present invention is 30 to 100,preferably 30 to 50, more preferably 39 to 50. The acid number of theemulsion polymer of the second and fourth aspects of the presentinvention is 4 to 100, preferably 8 to 50.

The emulsion polymer used in this invention is substantiallythermoplastic, or substantially uncrosslinked, when it is applied to thesurface, although low levels of deliberate or adventitious crosslinkingmay be present. When low levels of precrosslinking or gel content aredesired low levels of nonionic multi-ethylenically unsaturated monomerssuch as, for example, 0.1%-5%, by weight based on the weight of theemulsion-polymerized polymer, allyl methacrylate, diallyl phthalate,1,3-butylene glycol dimethacrylate, 1,6-hexanedioldiacrylate, anddivinyl benzene may be used. It is important, however, that the qualityof the film formation is not materially impaired.

The polymerization techniques used to prepare emulsion polymers are wellknown in the art. In the preparation of emulsion polymers conventionalsurfactants may be used such as, for example, anionic and/or nonionicemulsifiers such as alkali or ammonium alkyl sulfates, alkyl sulfonicacids, fatty acids, and oxyethylated alkyl phenols. The amount ofsurfactant used is usually up to 6% by weight, based on the weight oftotal monomer. Either thermal or redox initiation processes may be used.Conventional free radical initiators may be used such as, for example,hydrogen peroxide, t-butyl hydroperoxide, and ammonium and/or alkalipersulfates, typically at a level of 0.05% to 3.0% by weight, based onthe weight of total monomer. Redox systems using the same initiatorscoupled with a suitable reductant such as, for example, sodium bisulfitemay be used at similar levels. Chain transfer agents such as, forexample, alkyl mercaptans may be used in order to moderate the molecularweight of the polymer.

In another aspect of the present invention the emulsion polymer may beprepared by a multistage emulsion polymerization process, in which atleast two stages differing in composition are polymerized in sequentialfashion. Such a process usually results in the formation of at least twomutually incompatible polymer compositions, thereby resulting in theformation of at least two phases within the polymer particles. Suchparticles are composed of two or more phases of various geometries suchas, for example, core/shell or core/sheath particles, core/shellparticles with shell phases incompletely encapsulating the core,core/shell particles with a multiplicity of cores, and interpenetratingnetwork particles. In all of these cases the majority of the surfacearea of the particle will be occupied by at least one outer phase andthe interior of the particle will be occupied by at least one innerphase. Each of the stages of the multi-staged emulsion polymer maycontain the same monomers, surfactants, chain transfer agents, etc. asdisclosed herein-above for the emulsion polymer. In the case of amulti-staged polymer particle the Tg for the purpose of this inventionis to be calculated by the Fox equation as detailed herein using theoverall composition of the emulsion polymer without regard for thenumber of stages or phases therein. Similarly, compositional quantitiesfor a multi-staged polymer particle such as, for example, the amount offirst nonionic monomer and the acid number shall be determined from theoverall composition of the emulsion polymer without regard for thenumber of stages or phases therein. The polymerization techniques usedto prepare such multistage emulsion polymers are well known in the artsuch as, for example, U.S. Pat. Nos. 4,325,856; 4,654,397; and4,814,373.

The emulsion polymer has an average particle diameter less than 120nanometers, preferably less than 100 nanometers, more preferably lessthan 80 nanometers, most preferably less than 70 nanometers. Particlesizes herein are those determined using a Brookhaven Model BI-90particle sizer manufactured by Brookhaven Instruments Corporation,Holtsville N.Y. Reported as “effective diameter”.

The glass transition temperature (“Tg”) of the emulsion polymer is −20°C. to 100° C. Tgs used herein are those calculated by using the Foxequation (T. G. Fox, Bull. Am. Physics Soc., Volume 1, Issue No. 3, page123(1956)). that is, for calculating the Tg of a copolymer of monomersM1 and M2,1/Tg(calc.)=w(M1)/Tg(M1)+w(M2)/Tg(M2),wherein

-   Tg(calc.) is the glass transition temperature calculated for the    copolymer-   w(M1) is the weight fraction of monomer M1 in the copolymer-   w(M2) is the weight fraction of monomer M2 in the copolymer-   Tg(M1) is the glass transition temperature of the homopolymer of M1-   Tg(M2) is the glass transition temperature of the homopolymer of M2,    all temperatures being in ° K.

The glass transition temperatures of homopolymers may be found, forexample, in “Polymer Handbook”, edited by J. Brandrup and E. H.Immergut, Interscience Publishers.

The aqueous coating composition contains 0.25-10 wt. %, preferably 0.5-8wt. %, more preferably 1-8 wt. %, of a water-soluble alkoxylated amine,by which is meant herein an amine substituted with one, two, or three—(RO)_(x)R′ groups, where R is C₁-C₄ alkyl or mixtures thereof, mixturesdisposed randomly or in sequences (blocks), preferably ethyl, and wherex is from 5-100. Further, the amine may be substituted with 0-2 R″groups, where R″ is a C₁-C₂₄ alkyl, aralkyl, or aromatic group,preferably each R″ group is a C₁-C₂₄ alkyl selected such that the Iodinenumber of the water-soluble alkoxylated amine is less than 30, morepreferably such that the Iodine number of the water-soluble alkoxylatedamine is less than 15, inorder to minimize the color of the alkoxylatedamine. Preferred are t-amines. In any event the alkoxylated amine iswater-soluble at least to the amount that it is utilized in the aqueouscoating composition at 25 C. Typical alkoxylated amines are thecommercially available alkoxylated t-amines, Ethox SAM-50, Ethomeen18/25, and the primary alkoxylated amine, Jeffamine M-2070.

The amount of pigment in the aqueous coating composition may vary from apigment volume concentration (PVC) of 0 to 75 and thereby encompasscoatings otherwise described, for example, as clear coatings, semi-glossor gloss coatings, flat coatings, and primers.

The aqueous coating composition is prepared by techniques which are wellknown in the coatings art. First, if the coating composition is to bepigmented, at least one pigment is well dispersed in an aqueous mediumunder high shear such as is afforded by a COWLES® mixer or, in thealternative, at least one predispersed pigment may be used. Then theemulsion polymer, selected surfactant and alkyl polyglycoside is addedunder low shear stirring along with other coatings adjuvants as desired.Alternatively, either or both of the selected surfactant and alkylpolyglycoside may have been previously added to the emulsion polymerbefore, during, or subsequent to the preparation of the emulsionpolymer. Alternatively, the emulsion polymer may be present during thepigment dispersion step. The aqueous coating composition may containconventional coatings adjuvants such as, for example, emulsifiers,buffers, neutralizers, coalescents, thickeners or rheology modifiers,freeze-thaw additives, wet-edge aids, humectants, wetting agents,biocides, antifoaming agents, colorants, waxes, and anti-oxidants. Theaqueous coating composition may contain up to 75%, by weight based onthe total dry weight of the polymer, of an emulsion polymer not meetingthe limitations of the emulsion polymer of the first or second aspect ofthe present invention.

The solids content of the aqueous coating composition may be from 25% to60% by volume. The viscosity of the aqueous polymeric composition may befrom 50 KU (Krebs Units) to 120 KU as measured using a BrookfieldDigital viscometer KU-1; the viscosities appropriate for differentapplication methods vary considerably.

The presence and amount of friable material on a surface can bedetermined using the method of ASTM test method D-659. In this testmethod the lower the rating the more friable material present. The drycoating compositions of this invention have been evaluated and arebeneficially used over substrates having surfaces with a rating of 3 orless. A “friable surface” herein is defined as one which has a rating of3 or less determined by the above method. An alternative approach todetermining the presence and amount, actually the depth, of friablematerial, is to repeatedly adhere a piece of tape onto an area of thesurface and remove the friable material. This is continued until no morefriable material is visually detected on the tape. At that point thedepth can be determined quantitatively by using a suitable microscopictechnique such as scanning electron microscopy. Using this test methodwe found that the test substrates of the examples had at least 10microns of friable material on their surfaces.

Conventional coatings application methods such as, for example,brushing, rolling, and spraying methods such as, for example,air-atomized spray, air-assisted spray, airless spray, high volume lowpressure spray, and air-assisted airless spray may be used in the methodof this invention. The aqueous coating composition may be advantageoulyapplied to substrates such as, for example, weathered paint and friablecementitious substrates such as, for example, stucco and mortar but mayalso be applied to other architectural substrates. Drying is typicallyallowed to proceed under ambient conditions such as, for example, at 0°C. to 35° C.

The following examples are presented to illustrate the invention and theresults obtained by the test procedures.

The abbreviations listed below are used throughout the examples.

AA = Acrylic Acid AAEM = 2-(Actetoacetoxy) ethyl methacrylate BA = ButylAcrylate EHA = 2-Ethylhexyl Acrylate MMA = Methyl MAA = Methacrylic AcidMethacrylate STY = Styrene n-DDM = n-Dodecyl Mercaptan ALS = Ammoniumlauryl sulfate (28% active) VA = Vinyl Acetate SLS = Sodium laurylsulfate (28% active)

All polymerization examples were carried out in a four-neck, roundbottom glass flask equipped with a mechanical blade stirrer, athermocouple to monitor temperature, a reflux condenser, and a means toheat and cool.

EXAMPLE 1 Preparation of Emulsion Polymer

A 5 L flask was charged with 2016 g deionized water and heated to 87° C.while being swept with N₂. A monomer pre-emulsion was prepared from 395g deionized water, 12.9 g SLS, 1.5 g of sodium carbonate, 668.4 g BA,459.6 g MMA and 72 g MAA. 150 g SLS and 2.99 g of ammonium persulfatewere added to the flask along with 132 g deionized water. The monomerpre-emulsion was then added over 1.5 hours at 83° C. Over the course ofthe reaction, 0.66 g ammonium persulfate dissolved in 92 g deionizedwater was also added to the flask in a separate stream. When theadditions were complete, 54 g deionized water was added. The flask wascooled and 0.9 g 70% aqueous t-butyl hydroperoxide, 0.45 g sodiumformaldehyde sulfoxylate and a trace of iron sulfate heptahydrate wereadded in a total of 64 g of deionized water. The emulsion polymer had asolids content of 30.2% by weight, a particle size of 19 nm and a pH of5.1.

EXAMPLE 2 Preparation of Emulsion Polymer

A 5L flask was charged with 1461 g deionized water and heated to 87° C.while being swept with N₂. A monomer pre-emulsion was prepared from493.6 g deionized water, 16.1 g SLS, 835.5 g BA, 574.5 g MMA and 90 gMAA. 17.7 g SLS, 1.9 g sodium carbonate and 3.74 g of ammoniumpersulfate were added to the flask along with 165 g deionized water. Themonomer pre-emulsion was then added over 1.5 hours at 83° C. Over thecourse of the reaction, 0.82 g ammonium persulfate dissolved in 115 gdeionized water was also added to the flask in a separate stream. Whenthe additions were complete, 67 g deionized water was added. The flaskwas cooled and 1.1 g 70% aqueous t-butyl hydroperoxide, 0.56 g sodiumformaldehyde sulfoxylate and a trace of iron sulfate heptahydrate wereadded in a total of 75 g deionized water. The emulsion polymer had asolids content of 38.5% by weight, a particle size of 76 nm and a pH of5.1.

EXAMPLES 3-7 Preparation of Emulsion Polymers

The polymerization procedure of Example 2 was followed, with theexception that various amounts of sodium lauryl sulfate (SLS) were addedto the reaction kettle prior to monomer additions. The amounts andemulsion polymer characterization are presented in Table 3.1

TABLE 3.1 SLS amounts used in and characterization of Examples 3-7Particle Size EXAMPLE g SLS Wt. % solids in nm pH 3 49.3 38.3 47 5.0 48.04 38.5 95 5.0 5 3.96 38.5 118 5.1 6 2.04 38.7 186 5.3 7 1.02 38.7 2695.1

EXAMPLE 8 Preparation of Emulsion Polymer

The polymerization procedure of Example 2 was followed, with theexception that the monomer pre-emulsion was prepared with the followingmonomer charges: 835.5 g BA, 300 g MMA, 274.5 g STY, 90 g MAA. Theemulsion polymer had a solids content of 38.2% by weight, a particlesize of 78 nm and a pH of 5.3.

EXAMPLE 9 Preparation of Emulsion Polymer

The polymerization procedure of Example 2 was followed, with theexception that the monomer pre-emulsion was prepared with the followingmonomer charges: 757.5 g BA, 532.5 g MMA, 120 g AAEM, 90 g MAA. Theemulsion polymer had a solids content of 38.3% by weight, a particlesize of 83 nm and a pH of 5.0.

EXAMPLE 10 Preparation of Emulsion Polymer

5 L flask was charged with 1614 g deionized water and heated to 89° C.while being swept with N₂. A monomer pre-emulsion was prepared from 1080g deionized water, 10.6 g SLS, 743 g EA, 553 g MMA, 114 g AAEM, and 19 gMAA. 16 g SLS, 5.5 g ammonium persulfate, and 2.8% of the pre-emulsionwere added to the flask along with 110 g deionized water. The remainderof the monomer pre-emulsion was then added over 1.5 hours at 84-85° C.When the additions were complete, 30 g of deionized water was added. Theflask was cooled and 0.7 g of 70% aqueous t-butyl hydroperoxide, 0.4 gisoascorbic acid and a trace of iron sulfate heptahydrate were added ina total of 36.3 g deionized water. After the reaction mixture cooled toroom temperature, 10 g ammonium hydroxide was added. The emulsionpolymer had a solids content of 32.9% by weight, a particle size of 80nm and a pH of 8.4.

EXAMPLE 11 Preparation of Emulsion Polymer

A 5 L flask was charged with 1461 g of deionized water and heated to 87°C. while being swept with N₂. A monomer pre-emulsion was prepared from494 g deionized water, 16.1 g ALS, 768 g EHA, 575 g MMA, 37 g STY, 120 gMAA, and 8.5 g n-DDM. 120 g ALS, 2.5 g sodium carbonate, and 3.7 gammonium persulfate were added to the flask along with 165 g deionizedwater. The monomer pre-emulsion was then added over 1.5 hours at 83° C.Over the course of the reaction, 0.8 g ammonium persulfate dissolved in115 g deionized water was also added to the flask in a separate stream.When the additions were complete, 67 g deionized water was added. Theflask was cooled and 1.1 g of 70% aqueous t-butyl hydroperoxide, 0.6 gsodium formaldehyde sulfoxylate and a trace of iron sulfate heptahydratewere added in a total of 80 g deionized water. After the reactionmixture cooled to room temperature, 13 g ammonium hydroxide in 45 gdeionized water was added. The emulsion polymer had a solids content of37.3% by weight, a particle size of 45 nm and a pH of 6.4.

EXAMPLE 12 Preparation of Emulsion Polymer

A 5 L flask was charged with 1461 g deionized water and heated to 87° C.while being swept with N₂. A monomer pre-emulsion was prepared from 494g deionized water, 16.1 g ALS, 721.5 g EHA, 715.5 g MMA, 37.5 g STY,25.5 g MAA, and 8.5 g n-DDM. 120 g ALS, 0.5 g sodium carbonate, and 3.7g ammonium persulfate were added to the flask along with 165 g deionizedwater. The monomer pre-emulsion was then added over 1.5 hours at 83° C.Over the course of the reaction, 0.8 g ammonium persulfate dissolved in115 g deionized water was also added to the flask in a separate stream.When the additions were complete, 67 g of deionized water was added. Theflask was cooled and 1.1 g 70% aqueous t-butyl hydroperoxide, 0.6 gsodium formaldehyde sulfoxylate and a trace of iron sulfate heptahydratewere added in a total of 80 g deionized water. After the reactionmixture cooled to room temperature, 13 g ammonium hydroxide in 45 gdeionized water was added. The emulsion polymer had a solids content of34.4% by weight, a particle size of 40 nm and a pH of 6.5.

EXAMPLE 13 Preparation of Emulsion Polymer

A 5 L flask was charged with 1428 g deionized water and heated to 84° C.while being swept with N₂. A monomer pre-emulsion was prepared from 476g deionized water, 18.2 g SLS, 520.2 g BA, 1161.1 g VA and 18.7 g AA.35.7 g SLS, 1.7 g sodium bicarbonate, and 4.2 g ammonium persulfate wereadded to the flask along with 168 g deionized water. The monomerpre-emulsion was then added over 3 hours at 80° C. Over the course ofthe reaction, 0.9 g ammonium persulfate dissolved in 57 g deionizedwater was also added to the flask in a separate stream. When theadditions were complete, 68 g deionized water was added. The flask wascooled and 1.8 g 70% aqueous t-butyl hydroperoxide, 0.8 g sodiumformaldehyde sulfoxylate and a trace of iron sulfate heptahydrate wereadded in a total of 46 g deionized water. The emulsion polymer had asolids content of 42.5% by weight, a particle size of 78 nm and a pH of3.6.

EXAMPLE 14 Preparation of Emulsion Polymer

A 5 L flask was charged with 1461 g deionized water and heated to 85° C.while being swept with N₂. A monomer pre-emulsion was prepared from493.6 g deionized water, 16.1 g SLS, 468 g BA, 942 g of VA and 90 g MAA.17.7 g SLS, 1.5 g sodium bicarbonate and 3.74 g of ammonium persulfatewere added to the flask along with 165 g deionized water. The monomerpre-emulsion was then added over 3 hours at 80° C. Over the course ofthe reaction, 0.82 g ammonium persulfate dissolved in 115 g deionizedwater was also added to the flask in a separate stream. When theadditions were complete, 67 g deionized water was added. The flask wascooled and 1.1 g 70% aqueous t-butyl hydroperoxide, 0.56 g sodiumformaldehyde sulfoxylate and a trace of iron sulfate heptahydrate wereadded in a total of 75 g deionized water. The emulsion polymer had asolids content of 38.1% by weight, a particle size of 88 nm and a pH of3.5.

EXAMPLE 15 Preparation of Aqueous Coating Compositions

Using the ingredients given in Table 15.1 an aqueous coating compositionwas prepared. The grind premix was made and mixed on a high speed Cowlesdisperser for 20 minutes. The grind premix was transferred to anothercontainer and the let down ingredients were added in the order given.The final volume solids of the paint was 30 percent and the pigmentvolume concentration was 35%.

TABLE 15.1 Ingredients used in aqueous coatings composition MaterialWeight (grams) Grind Premix Water 50 Tamol 165 (Rohm and Haas) 4.04Ti-Pure R-960 (DuPont) 24.2 Atomite (Thompson, Weinman &Co) 20.7Beaverwhite (Luzenac America) 21.9 Attagel 50 (Engelhard Minerals andChemicals) 0.96 Acrysol RM-1020 (Rohm and Haas) 1.70 Drew L-475 (DrewChemical Company) 0.64 Let Down Emulsion polymer of Example 1 120.3Alkoxylated amine (Ethox SAM-50; 25% 7.1 in water from Ethox Chemicals)Propylene glycol 11.2 Texanol (Eastman Chemical) 4.7 Drew L-475 (DrewChemical Company) 1.3 Acrysol TT-615 (Rohm and Haas) 0.8 Aq. AmmoniumHydroxide (28%) 0.3 Acrysol RM-1020 (Rohm and Haas) 2.1 Acrysol RM-825(Rohm and Haas) 1.2 Water 3

EXAMPLES 16-31 AND COMPARATIVE EXAMPLES A-D Preparation of AqueousCoating Compositions

Using the same procedure as for Example 15, Examples 16-31 andComparative Examples A-D were prepared. Table 16.1 lists the differencesfrom Example 15 for each Example. As with Example 15 the PVC was 35percent and the Volume Solids was 30 percent for each of Examples 16-31and Comparative Examples A-D.

TABLE 16.1 Ingredients Used in Aqueous Coating Compositions Examples16-35 Weight % Emulsion Alkoxylated polymer of amine, based ExampleExample No. on Polymer Alkoxylated amine 16 3 4% Ethox SAM-50 17 2 4%Ethox SAM-50 18 4 4% Ethox SAM-50 19 5 4% Ethox SAM-50 Comparative A 64% Ethox SAM-50 Comparative B 7 4% Ethox SAM-50 20 2 2% Ethox SAM-50 212 1% Ethox SAM-50 22 2 0.5%   Ethox SAM-50 Comparative C 2 0% None 23 24% Ethomeen 18/25 (Akzo) 24 2 4% Jeffamine M-2070 (Huntsman) 25 11 4%Ethox SAM-50 Comparative D 12 4% Ethox SAM-50 26 10 4% Ethox SAM-50 2713 4% Ethox SAM-50 28 8 4% Ethox SAM-50 29 9 4% Ethox SAM-50 30 9 4%Jeffamine M-2070 31 14 4% Ethox SAM-50

EXAMPLES 32-34 AND COMPARATIVE EXAMPLE E Preparation of Aqueous CoatingCompositions

Using the same procedure as for Example 15, Examples 32-34 andComparative Example E were prepared. For Examples 33-34, the emulsionpolymers were mixed prior to making the aqueous coating composition. Aswith Example 15 the PVC was 35 percent and the Volume Solids was 30percent. Table 32.1 lists the pertinent information for each Example.

TABLE 32.1 Ingredients used in Examples 32-34 and Comparative Example EWeight % Emulsion Alkoxylated polymer of amine, based Example ExampleNo. on Polymer Alkoxylated amine Comparative E 6 4% Ethox SAM-50 32 3 4%Ethox SAM-50 33 6 + 3 4% Ethox SAM-50 65/35, by wt. 34 6 + 3 4% EthoxSAM-50 50/50, by wt.

EXAMPLE 35 AND COMPARATIVE EXAMPLES F-G Preparation of Aqueous CoatingCompositions

Comparative Example F was prepared using by adding 28.02 g emulsionpolymer of Example 6 to 32.5 g acrylic latex polymer (RHOPLEX AC-1801,Rohm and Haas Company) while stirring: To this mixture was added 137.5 gwater and 2 g TEXANOL coalescent. Comparative Example G was prepared ina similar manner using 28.98 g emulsion polymer of Example 3, 35.52 gacrylic latex polymer (RHOPLEX AC-1801), 2 g TEXANOL, and 136.5 g water.Example 42 was prepared in a similar manner using 25.89 g emulsionpolymer of Example 3, 1.59 g 25% aqueous solution of Ethox™ SAM-50,32.52 g acrylic latex polymer (RHOPLEX AC-1801), 2 g Texanol, and 138 gwater.

EXAMPLE 36 Evaluation of Adhesion to Weathered Paint Chalk

Chalk adhesion was evaluated for the aqueous coating compositions usingthe following procedure. The aqueous coating compositions were appliedusing a brush over a weathered piece of aluminum siding which had alayer of chalk about 25 microns thick. Chalk is the remnants of theinorganic particles (metal oxides, various silicates, and possibly metalcarbonates) that were used in the original paint.

The aqueous coating compositions were applied in two coats of 103 g/m²(1 gram per 15 in²). The first coat was allowed to dry for two hoursbefore application of the second coat. The coated panels were then driedfor approximately 24 hours. The panels were then placed in a light watermist-containing cabinet for approximately 18 hours. After exposure tothe water the painted panel was removed and allowed to dry under ambientconditions for 3 hours. ASTM cross hatch (X-hatch) tape pull test methodD-3359 was used to evaluate the adhesion. The percent of coatingretained after pulling off the tape was recorded. 100 indicates completeadhesion while 0 indicates complete removal. A value of 100 is desired;however, experience has shown that values of 20-25% or greater indicateacceptably good adhesion. The adhesion data is given in tables 1-36.5.

TABLE 36.1 Effect of particle size of emulsion polymer on chalk adhesionof dried aqueous coating compositions of Examples 15-19 and ComparativeExamples A-B Alkoxylated amine Particle size (SAM-50) wt. % X-hatchExample nm based on polymer adhesion 15 19 4% 93% 16 47 4% 56% 17 76 4%52% 18 95 4% 42% 19 118 4% 26% Comparative A 186 4%  6% Comparative B269 4%  8%

The dried aqueous coating compositions of Examples 15-19 of thisinvention having emulsion polymer particle sizes less than 120nanometers exhibit good chalk adhesion relative to Comparative ExamplesA-B.

TABLE 36.2 Effect of alkoxylated amine level on chalk adhesion of driedaqueous coating compositions of Examples 17-22 and Comparative Example CAlkoxylated amine Particle size (SAM-50) wt. % X-hatch Example nm basedon polymer adhesion 17 76 4% 52% 20 76 2% 40% 21 76 1% 41% 22 76 5% 30%Comparative C 76 0% 14%The dried aqueous coating compositions of Examples 17-22 of thisinvention having alkoxylated amine levels between 0.25-10 wt. % based onpolymer weight exhibit good chalk adhesion relative to ComparativeExample C.

TABLE 36.3 Effect of various alkoxylated amines on chalk adhesion ofdried aqueous coating compositions of Examples 17 and 23-24 andComparative Example C Particle size Alkoxylated amine X-hatch Example nmlevel and type adhesion 17 76 4% Ethox SAM-50 52% 23 76 4% Ethomeen18/25 50% 24 76 4% Jeffamine M2070 36% Comparative C 76 0% 14%

The dried aqueous coating compositions of Examples 17 and 23-24 of thisinvention having alkoxylated amine levels between 0.25-10 wt. % based onpolymer weight using various alkoxylated amines exhibit good chalkadhesion relative to Comparative Example C.

TABLE 36.4 Effect of emulsion polymer composition on chalk adhesion ofdried aqueous coating compositions of Examples 17, 25 and 26-31 andComparative Example D Composition and Particle Wt. % Alkoxylated X-hatchExample Acid Number size nm amine adhesion 17 55.7 BA/38.3 MMA/6 MAA 764% Ethox SAM-50 52% Acid No. = 39.06 25 51.2 EHA/38.3 MMA/7.98 MAA/2.5STY 45 4% Ethox SAM-50 51% Acid No. = 51.95 Comp. D 48.1 EHA/47.7MMA/1.7 MAA/2.5 STY 40 4% Ethox SAM-50 26% Acid No. = 11.07 26   52EA/38.7 MMA/8 AAEM/1.3 MAA 80 4% Ethox SAM-50 68% Acid No. = 8.46 2730.6 BA/68.3 VA/1.1 AA 78 4% Ethox SAM-50 32% Acid No. = 8.56 28 55.7BA/20 MMA/18.3 Sty/6 MAA 78 4% Ethox SAM-50 32% Acid No. = 39.06 29 50.5BA/35.5 MMA/8 AAEM/6 MAA 83 4% Ethox SAM-50 43% Acid No. = 39.06 30 50.5BA/35.5 MMA/8 AAEM/6 MAA 83 4% Jeff. M-2070 33% Acid No. = 39.06 31 31.2BA/62.8 VA/6 MAA 88 4% Ethox SAM-50 64% Acid No. = 39.06

The dried aqueous coating compositions of Examples 17, 25, and 28 ofthis invention incorporating emulsion polymers formed from nonionicmonomers having a water solubility of less than 8% and having an acidnumber greater of 30 to 100 exhibit good chalk adhesion relative toComparative Example D. The dried aqueous coating compositions ofExamples 26-27 and 29-31 of this invention incorporating emulsionpolymers formed 8-99.5%, by weight based on emulsion polymer weight, ofa copolymerized ethylenically unsaturated first nonionic monomer havinga water solubility of 8% or more and having an acid number greater of 4to 100 exhibit good chalk adhesion.

TABLE 36.5 Effect of blending emulsion polymers having particle sizesgreater than 120 nanometers with aqueous coating compositions of thisinvention on chalk adhesion of dried aqueous coating compositions ofExamples 33-34 Wt. % alkoxylated X-hatch Example Particle size nm amineEthox SAM-50 adhesion Comparative E 186 4%  3% 32  47 4% 33% 33 25 wt. %47 + 4% 21% 75 wt. % 186  34 50 wt. % 47 + 4% 42% 50 wt. % 186 

The dried aqueous coating compositions of Examples 33-34 of thisinvention exhibit good chalk adhesion when an emulsion polymer of thisinvention makes up at least 25% by weight of the total emulsion polymersused in the coating.

EXAMPLE 37 Evaluation of Adhesion to a Cementitious Surface

A substrate simulating a weathered, chalky cementitious surface and/or apoorly consolidated cementitious surface was prepared. 24 grams of a 2%aqueous solution of hydroxyethyl cellulose (Natrosol™ 250 MBR), 7 gramsTiO₂, 60 grams CaCO₃, and 9 grams water were mixed on a high speeddisperser. A 100 micron thick wet film of the material was applied to aglass plate and allowed to dry for 48 hours at 50% relative humidity and23° C. Then a 100 micron wet film thickness of aqueous coatingcomposition was applied to the substrate. This coating was allowed todry for 7 days. ASTM cross hatch tape pull test method D-3359 was thenused to evaluate the adhesion. The values are presented in Table 44.1 aspercent coating retained.

TABLE 44.1 Simulated cementitious surface adhesion of dried aqueouscoating compositions of Example 35 and Comparative Examples F-G Wt. %alkoxylated amine X-hatch Example Particle size nm (Ethox SAM-50)adhesion Comparative F 269 0% 40% Comparative G 47 0% 60% 35 47 4% 90%

The dried aqueous coating compositions of example 35 of this inventionexhibits superior cementitious surface adhesion relative to comparativesamples F-G.

1. A method for coating a friable surface comprising forming an aqueouscoating composition comprising an emulsion polymer having a glasstransition temperature of −20° C. to 100° C. and an average particlediameter less than 120 nanometers, said emulsion polymer consistingessentially of at least one copolymerized ethylenically unsaturatednonionic monomer, each of said nonionic monomer(s) having a watersolubility less than 8% by weight, and at least one copolymerized acidmonomer, such that the acid number of said emulsion polymer is 30 to100, and 0.5-10%, by weight based on said emulsion polymer weight,water-soluble alkoxylated amine; applying said aqueous coatingcomposition to a friable surface; and drying, or allowing to dry, saidaqueous coating composition.
 2. The method of claim 1 wherein the acidnumber of said emulsion polymer is 39 to
 50. 3. The method of claim 1wherein the average particle size of said emulsion polymer is less than80 nanometers.
 4. A method for coating a friable surface comprisingforming an aqueous coating composition comprising an aqueous emulsionpolymer having a glass transition temperature of −20° C. to 100° C. andan average particle diameter less than 120 nanometers, said emulsionpolymer consisting essentially of 8-99.5%, by weight based on saidemulsion polymer weight, of at least one copolymerized ethylenicallyunsaturated first nonionic monomer, each of said first nonionicmonomer(s) having a water solubility of 8% by weight or more, 0-91.5%,by weight based on said emulsion polymer weight, of at least onecopolymerized ethylenically unsaturated second nonionic monomer, each ofsaid second nonionic monomer(s) having a water solubility of less than8%, and at least one copolymerized acid monomer, such that the acidnumber of said emulsion polymer is 4 to 100; and 0.5-10%, by weightbased on said emulsion polymer weight, water-soluble alkoxylated amine,applying said aqueous coating composition to a friable surface; anddrying, or allowing to dry, said aqueous coating composition.